When we went to the moon, we did it for a reason. So we could do science there. 40 years ago there was no such thing as rovers. If scientists wanted an experiment conducted on the moon they needed a man there to conduct it. In todays world we have rovers. They last much longer than humans, dont require any food or oxygen and can survive in a much larger range of environments than humans can.
We didn’t go there so we could say “Hey we put a man on the moon isn’t that cool?” You can’t have that as a main reason to do something. Doing stuff because it’s cool isn’t the governments job. It has to have measurable benefits.
I have never heard any argument to send someone to Mars other than “it will inspire people”. It’s great to inspire people. But I imagine that $500,000,000,000 (the cost of putting a man on mars) could do a lot more than merely inspire people – think how far it could go towards solving world poverty.
I honestly don’t believe it will inspire people very much anyway. We’re very much aware of our capabilities. If we already knew we can go to Mars, how does actually going there prove anything or inspire anyone?
The money would be better spent focusing on building a moon base. I think it’s essential to do this, following Stephen Hawking’s reasoning about improving our chances of survival as the human race. If a deadly virus break out or a meteor is heading towards Earth, what are we going to do? We must spread our civilization to other planets – let’s not put all our eggs in this one basket we call Earth.